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  <script>
    let NianLing = 20; // 大驼峰
    let MaxAge = 20; // 大驼峰
    let maxAge = 20; // 小驼峰
    let max_age = 20; // 匈牙利命名
    let age = 20;

    // let let;
    // let 😀;
    // let 年龄;
    // let abc123_$*;
    // let abc123;
    // let 123abc;
    // let 1age;
  </script>
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